WALNUT CREEK — For years, Larry Loomer did what many people do when challenged to think about the Big One — the catastrophic earthquake that experts predict will happen sooner rather than later in California.

He largely ignored it.

Sure, he knew to check the gas line, stock water, store emergency supplies, and select a designated family meeting place. But in 2005, curious to know more, he took a Walnut Creek CERT class. The 20-hour Community Emergency Response Team course provided valuable information and certified the now 74-year-old Concord resident as a volunteer disaster service worker in the event of an emergency.

“At graduation, they gave us FRS radios,” recalls Loomer. The family radio service radios are like walkie-talkies, capable of reaching house-to-house within an average residential block. “But they’re not able to reach from my house to the local police department emergency operation center. I asked how to get messages to the place where things will be coordinated in an emergency. They said ham radio. That’s what got me started.”

That hook — the desire for safety — and other impetus attracts a worldwide community to ham radios, the late 19th-century technology that is celebrated annually on the fourth weekend of June. The Mt. Diablo Amateur Radio Club hosts this year’s free annual Field Day on June 25-26, at Heather Farm Park in Walnut Creek.

For 24 continuous hours, amateur radio operators demonstrate emergency and nonemergency communication techniques. Club members explain the use of solar power, batteries, generators and antennas that provide vital support for emergency response teams and residents when standard systems are no longer available.

With the advent of the internet and the general public’s reliance on cell phones, Field Day introduces the latest digital modes that communicate from laptops or tablets to ham radios. Loomer is this year’s event coordinator and chair.

“Mesh Net and Fldigi are two programs that transmit digital information and translate it so it can be sent and stored using amateur radio frequencies. You fill out a message form on a laptop with all your information and it’s filed in the right places in the system. When cell towers are not operational, ham radios will be,” says Loomer.

EchoLink is a technology that allows a ham operator to call up a local repeater (in the East Bay, it’s located on Mount Diablo). Without using megawatts of power or requiring complex antennas, operators connect with a 4-digit code to another repeater in a distant location.

“I can reach even somewhere far, like Birmingham, England,” says Loomer. “It translates the message and can send it anywhere. There are EchoLink nodes all over the country. I don’t have to have fancy antennas or generate as much power to send signals.”

In addition to education and information, Field Day offers radio licensing tests, including upgrades for people with existing licenses, and radio quality testing.

“Especially with cheaper radios, there can be frequencies right next to the one they’re supposed to be on. We make sure the radios are clean and the frequency is perfect,” says Loomer.

In 2015, the solar power trailer owned by a ham operator known by the call sign, “KG6PHZ,” attracted the most attention. “He’s added two panels this year. That nine-panel array provides the power that we use for the whole Field Day. We don’t have to use smelly generators: we’re kind of self-contained in that way,” Loomer says.

A barbecue at 6 p.m. treats evening visitors and those people staying overnight in RV’s and tents to a free dinner, another draw for the approximately 50 people who attended last year.

Of course, ham radios are also an oldfangled social media tool and in that respect, Field Day is a retro-party set in the 21st century. There’s a reality TV-style competition to connect during the 24-hour period to as many of the 35,000 radio amateurs all over the world as possible.

Loomer, whose ham radio interest is more in supporting public service activities — parades, bike and other race competitions — says last year’s event was a thrill to observe.

“We’re getting new hams all the time, so the numbers are growing,” he said. ” There’s still a novelty and excitement I see when people connect and talk with someone in a foreign land.”

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